Extra blue light is not needed in FW tanks. Until I got a few LED lights, all of my lighting was full spectrum high CRI. But the LEDs have controls for blue and brightness and white levels. I turn the blue setting as low as possible and I do not run any form of light overnight. In the wild there are no blue night lights.
Nocturnal fish in the wild do not have any special lighting happening. They are able to function fine in what we think is dark but they do not. many of my corys are pretty active during the day. I have no idea what they are up to at night except I can see them swimming around because the room is still lighted and that means the tank is not truly dark.
When I ran my only pressurized CO2 planted tank I did not use a solenoid and pH controller. I ran a leaner mix of co2 24/7. That tank had the fewest health type issues with the fish. But it required so much pruning and replanting that it was taking up too much time. I took it apart and repurposed it. I have had as many as 13 planted tanks going and they were all low to medium light set-ups. They all had different plants abd inhabitabnts. I have also had tanks which had no plants and the lights were only used when I worked in the tank as I needed to see what I was doing. The only lighting otherwise was what cane in via windows or from room lighting.
The one thing I know for sure is that every tank is different. What makes it work well is specific to that tank. This means there are a lot of guidelines we might use but in the end we have to figure out for each tank what actually works well and then to stick with it unless there is a real reason to change things. When we must do is learn to change things when they are not working well for the fish etc.
For me it is important that lighting allows the fish to look like they would in the wild under sunlight. There is a measure of this for articficial lighting called CRI- color rendering index:
"The Color Rendering Index (CRI) is a measure that indicates how accurately a light source displays colors compared to natural light, with a scale from 0 to 100. A higher CRI value means colors appear more vibrant and true to life, making it important for applications like photography and interior design."
Until LEDs, all of my bulbs have had a CRI of 90 or better. I have a few T-8 fluor. Zoo Med bulbs with a CRI of 98. "The Ultra Sun is a 6500K high intensity trichromatic full spectrum daylight lamp. With a CRI rating of 98, it provides excellent color reduction." I love how things look and how well plants do under this bulb.
